osborn



T. OSBORN SPARK PLUG Nov. 9 1926. 1,605,976

Filed August 14., 192:

11. 063507 2, I gwuqaloz.

Patented Nov. 9, 1926.

'U N l T ED T 2 h 155 THOMAS OSBO'RIL-OF CENT-ERVZLLE, IOWA.

" SPARK .rnUe.

Application filed August '14, 1923. Serial No. 657,400.

One object of this invention is to provide a spark plug which is so constructed that leakage of compression and the passing of oil through the. plug will be reduced to a minimum, a substantially hermetic closure being effected without appreciable danger of breaking the core of the plug.

It is within the province of the disclosure to improve generally and to enhance the utility of devices of that type to which the invention appertains.

With the above and other objects in View, which will appear the description procoeds, the invention resides in the combination and arrangement 01 parts and in the details oi ronstruction hereinafter described and claimed, it being understood that, with in the scope of what is claimed, changes in the precise embodiment of the invention shown can be made without departing from the spirit of the invention.

In the accompanying drawings:

Figure 1 shows in longitudinal section, a plug constructed in accordance with the invention, parts being in elevation; Figure 2 is a cross section on the line 22 of Figure 1; Figure 8 is a cross section on the line 83 of Figure 1; Figure 1 is a cross section on the line 4:4 of Figure 1.

The plug forming the subject matter of this application comprises a metal casing l which is externally threaded as at 2 for engagement with the cylinder of an internal combustion engine. At its inner end, the casing 1 has a bore 8, the inner end of the casing carrying an electrode 4c. The casing 1 has an internal shoulder 5 which is inclined toward the inner end of the plug, the shoulder being located at one end of the bore 3.

The casing 1 has an internal shoulder 6 located at right angles to the axis of the easing 1. The casing l is provided with an external wrench-receiving part 7.

The core of the plug is marked by the numeral 8 and is made of porcelain or any other suitable substance. The Core 8 in cludes a neck 9, an enlarged body 10 and a reduced foot 11 provided with a recess 12 defining an internal shoulder let located in the body 10 of the core. The body 10 of the core has an inclined surface 15 disposed parallel to the inclined shoulder 5 in the casing 1. At a point adjacent to the shoulder 6 in the casing 1, the body 10 of the core 8 has an inclined surface 16 which slopes in a direction opposite to that inner end of the recess 12 in the core 8.

in which the surface '15 slopes. A -compressible washer 17 made of copper and asbestos or any other suitable materials, rests on the shoulder 5 of the casing 1 and receives the foot 11 of the core, the washer 17 being bound between the shoulder 5 and the in clined surface 15 of the body 10 of the core 8. compressible washer 18 rests on the shoulder 6 of the casing 1 and is beveled as at 19, to cooperate with the inclined surface 16 of the body 10 of the core 8. A metal washer 21' is located in the casing 1 and rests on the washer 18. Both the upper and lower surface of the metal washer 21 preferably are smooth. A sleeve 22 is threaded into the casing 1 and has a rounded lower end 28 bearii'ig on the washer 21.

An elect-rode 24: extends through the core 8 longitudinally thereof, the same being provided intermediate its ends, with a projection 25 engaging an asbestos washer bearing against the shoulder 14 which exist-s at the A washer 26 surrounds the electrode 24: and en gages the upper end of the core 8, a binding nut 27 being threaded on the end of the elec trode 24 and the washer 26 being interposed between the nut 27 and the core 8.

In practical operation, when the sleeve 22 is threaded into the body 1, the sleeve rotates readily on the metal washer 21, because the lower end of the sleeve is rounded as at 23. Owing to the fact that the washer 21 is interposed between the sleeve 22 and the washer 18, the last mentioned washer is not worn unduly, or injured by contact with the sleeve 22. The washer 18 is compressed and expands inwardly bridging the space between the casing 1 and the core 8, the washer 18 cooperating with the inclined surface 16 of the body 10 of the core 8 to secure an hermetic closure. When the core 8 is crowded downwardly into the casing 1 by the action of the sleeve 22, the compressible washer 17, cooperating with the inclined surface 5 of the casing 1 and with the surface 15 of the body 10 of the core 8, is compressed and is caused to expand inwardly, the washer enclosing the foot 11 of the core and providing an hermetic closure. It will be seen from the foregoing that the plug is sealed at two places, longitudinally of the plug and that a leakage of compression will be practically impossible, the compressible washers 17 and 18 preventing the core 8 of the plug from being broken when the sleeve 22 is advanced.

What is claimed is:

A spark plug comprising a casing; a core in the casing; a compressible gasket Within thecasing andabout the core; a metal washer Within the casing and about the core, the washer bearing upon the gasket and having a smooth outer surface; and a sleeve threaded into the casing and having a transverse- 1y rounded inner end surface which engages the smooth outer surface of the Washer, said 10 surfaces cooperating to prevent the Washer from rotating upon the gasket when the sleeve is rotated.

In testimony that I claim the foregoing as my own, I have hereto afiixed my signa- 15 ture.

THOMAS OSBORN. 

